BS::thread_pool v3.1.0

v3.1.0 (2022-07-13)

• BS_thread_pool.hpp:
  • Fixed an issue where wait_for_tasks() would sometimes get stuck if push_task() was executed immediately before wait_for_tasks().
  • Both the thread pool constructor and the reset() member function now determine the number of threads to use in the pool as follows. If the parameter is a positive number, then the pool will be created with this number of threads. If the parameter is non-positive, or a parameter was not supplied, then the pool will be created with the total number of hardware threads available, as obtained from std::thread::hardware_concurrency(). If the latter returns a non-positive number for some reason, then the pool will be created with just one thread. See #51 and #52.
  • Added the [[nodiscard]] attribute to classes and class members, in order to warn the user when accidentally discarding an important return value, such as a future or the return value of a function with no useful side-effects. For example, if you use submit() and don't save the future it returns, the compiler will now generate a warning. (If a future is not needed, then you should use push_task() instead.)
  • Removed the explicit specifier from all constructors, as it prevented the default constructor from being used with static class members. See #48.
• BS_thread_pool_test.cpp:
  • Improved count_unique_threads() using condition variables, to ensure that each thread in the pool runs at least one task regardless of how fast it takes to run the tasks.
  • When appropriate, check() now explicitly reports what the obtained result was and what it was expected to be.
  • check_task_monitoring() and check_pausing() now explicitly report the results of the monitoring at each step.
  • Changed all instances of std::vector<std::atomic<bool>> to std::unique_ptr<std::atomic<bool>[]>. See #44.
  • Converted a few more C-style casts to C++ cast expressions.
• README.md:
  • Added instructions for using this package with the Conan C/C++ package manager. Please refer to this package's page on ConanCenter to learn how to use Conan to include this package in your project with various build systems.
• If you found this project useful, please consider starring it on GitHub! This allows me to see how many people are using my code, and motivates me to keep working to improve it.